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Re: [Geopriv] Re: [Ecrit] Not-so-grand compromise on how to doendpointce

Subject: Re: [Geopriv] Re: [Ecrit] Not-so-grand compromise on how to doendpointcentric LCP without giving away the store
From: Henning Schulzrinne
Date: Mon, 16 Apr 2007 13:48:47 -0400
We have such a mechanism, in progress at least: The SIP configuration framework (see http://tools.ietf.org/html/draft-ietf-sipping-config- framework-11). It supports SIP-based event notifications for configuration updates. As I said in an earlier message, re-inventing a subset of the configuration framework just for this purpose seems counterproductive.

On Apr 16, 2007, at 1:35 PM, Brian Rosen wrote:

Okay, let's look at this.

For fixed devices, the PSAP URI doesn't change often, the cached value is very likely to be good. However, it MIGHT change on short notice. The call
time query fixes this, if it works.

For mobile devices, the endpoint may get a reference. The REFERENCE doesn't
change.  It's good for a long time (probably as long as the carrier -
subscriber relationship holds). If it gets a value, then it wants an update when it moves beyond the PSAP boundary. With a value, it queries LoST and gets the boundary, then passes that to its location determination mechanism
and asks for a notification when it moves beyond that.

The above, of course, is fairly far from what IMS currently talks about, but
that is what the IETF ecrit/presence architecture would say.

If the access network plays cozy with the location, so it passes a reference and a PSAP URI, then it needs a way to TELL the device when the PSAP URI is
no longer valid.  Perhaps we could define a SIP event package for this
purpose, so a LIS could notify an endpoint of a new PSAP URI when its
current location warranted that. I suppose this is a presence thing, and maybe we could tie this more strongly into the existing presence system.


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